Goals from Keshi Anderson and Harry Smith earned Swindon a 2-0 Sky Bet League Two victory over Cambridge at the Energy Check County Ground.
The visitors had started the brighter but failed to capitalise on their early dominance.
In the sixth minute the home fans were calling for a red card following Gary Deegan's strong tackle on Kellan Gordon, but the referee deemed it only worthy of a yellow.
The Robins took the lead in the 13th minute when Anderson latched on to a loose ball in the area and fired a low right-footed shot past David Forde.
In the 44th minute the away side claimed for a penalty after a challenge on George Maris but the referee waved play on.
Cambridge nearly levelled in the 74th minute when Uche Ikpeazu met a Brad Halliday cross but his effort hit the crossbar.
Two minutes from time Smith was able to latch on a throughball by John Goddard and fired home to ensure the victory for Swindon.